A View on the Importance of “Multi-Attribute Method” for Measuring Purity of Biopharmaceuticals and Improving Overall Control Strategy

Implementation of a LC-MS based multi-attribute method (MAM) and intact multi-attribute method (iMAM) workflow for the characterisation of a GLP-Fc fusion protein

Over the past few years, the implementation of mass spectrometry (MS) in QC laboratories has become a more common occurrence. The multi-attribute method (MAM), and emerging intact multi-attribute method (iMAM), are powerful analytical tools utilising liquid chromatography-mass spectrometry (LC-MS) methods that enable the monitoring of critical quality attributes (CQAs) in biotherapeutic proteins in compliant settings. Both MAM and iMAM are intended to replace or supplement several conventional assays with a single LC-MS method utilising MS data in combination with robust, semi-automated data processing workflows. MAM and iMAM workflows can also be implemented into current Good Manufacturing Practices environments due to the availability of CFR 11 compliant chromatography data system software. In this study, MAM and iMAM are employed for the analysis of 4 batches of a glucagon-like peptide-Fc fusion protein. MAM approach involved a first the discovery phase for the identification of CQAs and second, the target monitoring phase of the selected CQAs in other samples. New peak detection was performed on the data set to determine the appearance, absence or change of any peak. For native iMAM workflow both size exclusion and strong cation exchange chromatography were optimized for the identification and monitoring of CQAs at the intact level.

Advances and opportunities in process analytical technologies for viral vector manufacturing

Viral vectors are an emerging, exciting class of biologics whose application in vaccines, oncology, and gene therapy has grown exponentially in recent years. Following first regulatory approval, this class of therapeutics has been vigorously pursued to treat monogenic disorders including orphan diseases, entering hundreds of new products into pipelines. Viral vector manufacturing supporting clinical efforts has spurred the introduction of a broad swath of analytical techniques dedicated to assessing the diverse and evolving panel of Critical Quality Attributes (CQAs) of these products. Herein, we provide an overview of the current state of analytics enabling measurement of CQAs such as capsid and vector identities, product titer, transduction efficiency, impurity clearance etc. We highlight orthogonal methods and discuss the advantages and limitations of these techniques while evaluating their adaptation as process analytical technologies. Finally, we identify gaps and propose opportunities in enabling existing technologies for real-time monitoring from hardware, software, and data analysis viewpoints for technology development within viral vector biomanufacturing.

Rapid Mass Spectrometry-Based Multiattribute Method for Glycation Analysis with Integrated Afucosylation Detection Capability

The multiattribute method (MAM) has emerged as a powerful tool for simultaneously screening multiple product quality attributes of therapeutic antibodies. One such potential critical quality attribute (CQA) is glycation, a common modification that can impact the heterogeneity, functional activity, and immunogenicity of therapeutic antibodies. However, current methods for monitoring glycation levels in MAM are rare and not sufficiently rapid and accurate. In this study, an improved mass spectrometry (MS)-based MAM was developed to simultaneously monitor glycation and other quality attributes including afucosylation. The method was evaluated using two therapeutic antibodies with different glycosylation site numbers. Treatment with IdeS, Endo F2, and dithiothreitol generated three distinct subunits, and the glycation results obtained were similar to those treated with PNGase F, which is routinely used to release glycans; the sample processing time was greatly reduced while providing additional quality attribute information. The MS-based MAM was also employed to assess the glycation progression following forced glycation in various buffer solutions. A significant increase in oxidation was observed when forced glycation was conducted in an ammonium bicarbonate buffer solution, and a total of 23 potential glycation sites and 4 significantly oxidized sites were identified. Notably, we found that ammonium bicarbonate was found to specifically stimulate oxidation, while glycation had a synergistic effect on oxidation. These findings establish this study as a novel methodology for achieving a technologically advanced platform and concept that enhances the efficacy of product development and quality control, characterized by its broad-spectrum, rapid, and accurate nature.

Basic regulatory science behind drug substance and drug product specifications of monoclonal antibodies and other protein therapeutics

In this review, we focus on providing basics and examples for each component of the protein therapeutic specifications to interested pharmacists and biopharmaceutical scientists with a goal to strengthen understanding in regulatory science and compliance. Pharmaceutical specifications comprise a list of important quality attributes for testing, references to use for test procedures, and appropriate acceptance criteria for the tests, and they are set up to ensure that when a drug product is administered to a patient, its intended therapeutic benefits and safety can be rendered appropriately. Conformance of drug substance or drug product to the specifications is achieved by testing an article according to the listed tests and analytical methods and obtaining test results that meet the acceptance criteria. Quality attributes are chosen to be tested based on their quality risk, and consideration should be given to the merit of the analytical methods which are associated with the acceptance criteria of the specifications. Acceptance criteria are set forth primarily based on efficacy and safety profiles, with an increasing attention noted for patient-centric specifications. Discussed in this work are related guidelines that support the biopharmaceutical specification setting, how to set the acceptance criteria, and examples of the quality attributes and the analytical methods from 60 articles and 23 pharmacopeial monographs. Outlooks are also explored on process analytical technologies and other orthogonal tools which are on-trend in biopharmaceutical characterization and quality control.

What is the role of current mass spectrometry in pharmaceutical analysis?

The role of mass spectrometry (MS) has become more important in most application domains in recent years. Pharmaceutical analysis is specific due to its stringent regulation procedures, the need for good laboratory/manufacturing practices, and a large number of routine quality control analyses to be carried out. The role of MS is, therefore, very different throughout the whole drug development cycle. While it dominates within the drug discovery and development phase, in routine quality control, the role of MS is minor and indispensable only for selected applications. Moreover, its role is very different in the case of analysis of small molecule pharmaceuticals and biopharmaceuticals. Our review explains the role of current MS in the analysis of both small-molecule chemical drugs and biopharmaceuticals. Important features of MS-based technologies being implemented, method requirements, and related challenges are discussed. The differences in analytical procedures for small molecule pharmaceuticals and biopharmaceuticals are pointed out. While a single method or a small set of methods is usually sufficient for quality control in the case of small molecule pharmaceuticals and MS is often not indispensable, a large panel of methods including extensive use of MS must be used for quality control of biopharmaceuticals. Finally, expected development and future trends are outlined.

Assessment of monoclonal antibody glycosylation: a comparative study using HRMS, NMR, and HILIC-FLD

Monoclonal antibodies (mAbs) represent the largest class of therapeutic protein drug products. mAb glycosylation produces a heterogeneous, analytically challenging distribution of glycoforms that typically should be adequately characterized because glycosylation-based product quality attributes (PQAs) can impact product quality, immunogenicity, and efficacy. In this study, two products were compared using a panel of analytical methods. Two high-resolution mass spectrometry (HRMS) workflows were used to analyze N-glycans, while nuclear magnetic resonance (NMR) was used to generate monosaccharide fingerprints. These state-of-the-art techniques were compared to conventional analysis using hydrophilic interaction chromatography (HILIC) coupled with fluorescence detection (FLD). The advantages and disadvantages of each method are discussed along with a comparison of the identified glycan distributions. The results demonstrated agreement across all methods for major glycoforms, demonstrating how confidence in glycan characterization is increased by combining orthogonal analytical methodologies. The full panel of methods used represents a diverse toolbox that can be selected from based on the needs for a specific product or analysis.

Improved Mass Accuracy and Precision for Multi-Attribute Methods Using a New Internally Calibrated High Resolution Orbitrap Mass Detector

In the development of biotherapeutics, a thorough understanding of a molecule's product quality attributes (PQAs) and their effect on structure-function relationships and long-term stability is essential for ensuring the safety and efficacy of the product. First published in 2015, the multi-attribute method (MAM), based on LC-MS peptide mapping and automation principles, can be used to support biotherapeutic process and product development. The MAM provides simultaneous site-specific detection, identification, quantitation, and quality control monitoring of selected PQAs. In this article, a low-maintenance MAM-ready mass detector with a small footprint was evaluated for its ability to monitor PQAs on proteolytically digested proteins with high mass accuracy and precision. Optimized source parameters enable robust relative quantitation of attributes with high sensitivity and minimal in-source fragmentation. A combination of a built-in one-point mass calibration procedure prior to data acquisition and Scan-to-Scan on-the-fly mass correction allows monitoring of most peptides for at least 54 days with sub-1 ppm mass accuracies at high-resolution (180,000 at m/z 200). This enables the use of <3 ppm mass tolerances for peptide monitoring, supporting high method specificity and robustness. LC-MS based MAM data from this instrument compares well to data collected by earlier MAM systems and conventional HPLC profile-based drug substance release assays.

Mass spectrometry study on SARS-CoV-2 recombinant vaccine with comprehensive separation techniques to characterize complex heterogeneity

SARS-CoV-2, the causative agent of COVID-19, has imposed a major public health threat, which needs effective therapeutics and vaccination strategies. Several potential candidate vaccines being rapidly developed are in clinical evaluation and recombinant vaccine has gained much attention thanks to its potential for greater response predictability, improved efficacy, rapid development and reduced side effects. Recombinant vaccines are designed and manufactured using bacterial, yeast cells or mammalian cells. A small piece of DNA is taken from the virus or bacterium against which we want to protect and inserted into the manufacturing cells. Due to the extremely complex heterogeneity of SARS-CoV-2 recombinant vaccine, single technology platform cannot achieve thorough and accurate characterization of such difficult proteins so integrating comprehensive technologies is essential. This study illustrates an innovative workflow employing multiple separation techniques tandem high-resolution mass spectrometry for comprehensive and in-depth characterization of SARS-CoV-2 recombinant vaccine, including ultra-high performance liquid chromatography (UHPLC), ion exchange chromatography (IEX) and imaged capillary isoelectric focusing (icIEF). The integrated methodology focuses on the importance of cutting-edge icIEF-MS online coupling and icIEF fractionation applied to revealing the heterogeneity secret of SARS-CoV-2 recombinant vaccine.

What should next-generation analytical platforms for biopharmaceutical production look like?

Biotherapeutic products, particularly complex products such as monoclonal antibodies (mAbs), have as many as 20-30 critical quality attributes (CQAs), thereby requiring a collection of orthogonal, high-resolution analytical tools for characterization and making characterization a resource-intensive task. As discussed in this Opinion, the need to reduce the cost of developing biotherapeutic products and the need to adopt Industry 4.0 and eventually Industry 5.0 paradigms are driving a reappraisal of existing analytical platforms. Next-generation platforms will have reduced offline testing, renewed focus on online testing and real-time monitoring, multiattribute monitoring, and extensive use of advanced data analytics and automation. They will be more complex, more sensitive, resource lean, and more responsive compared with existing platforms.

Quantitative analysis of residual aurintricarboxylic acid in biotherapeutic process streams using liquid chromatography triple quadrupole mass spectrometry

Aurintricarboxylic acid (ATA) is an excipient that can be added to the therapeutic protein manufacturing process as a component of the Chinese hamster ovary (CHO) cell culture media. ATA inhibits cell apoptosis and promotes cell growth in both serum-free and protein-free media. The addition of ATA is beneficial to the manufacturing process at the cell growth stage, however, residual ATA not consumed by cells can have toxicological effects on patients and its removal is required during downstream processing. To ensure manufacturing control and patient safety, the determination of residual ATA during downstream processing of biotherapeutics is required. The aim of this study was to develop and validate a liquid chromatography triple quadrupole mass spectrometry method for monitoring process clearance of ATA during downstream processing. Chromatographic separation of ATA was achieved using a 50 × 3 mm, 3 µm Imtakt Cadenza HS-C18 column and a triple quadrupole mass spectrometer operated in selected reaction monitoring mode was used for sensitive and specific detection. Linearity was assessed over a range of 62.5 ng/mL to 2000 ng/mL. Accuracy and precision were within 20% of the theoretical spike levels across the three concentration levels evaluated utilising two different antibodies, an IgG1 and an IgG4. Analyte specificity and selectivity were deemed acceptable based on no extraneous peaks detected. The method was successfully applied to monitoring process clearance of ATA in a tangential flow filtration (TFF) unit operation for downstream processing of monoclonal antibodies.

A candidate antibody drug for prevention of malaria

Over 75% of malaria-attributable deaths occur in children under the age of 5 years. However, the first malaria vaccine recommended by the World Health Organization (WHO) for pediatric use, RTS,S/AS01 (Mosquirix), has modest efficacy. Complementary strategies, including monoclonal antibodies, will be important in efforts to eradicate malaria. Here we characterize the circulating B cell repertoires of 45 RTS,S/AS01 vaccinees and discover monoclonal antibodies for development as potential therapeutics. We generated >28,000 antibody sequences and tested 481 antibodies for binding activity and 125 antibodies for antimalaria activity in vivo. Through these analyses we identified correlations suggesting that sequences in Plasmodium falciparum circumsporozoite protein, the target antigen in RTS,S/AS01, may induce immunodominant antibody responses that limit more protective, but subdominant, responses. Using binding studies, mouse malaria models, biomanufacturing assessments and protein stability assays, we selected AB-000224 and AB-007088 for advancement as a clinical lead and backup. We engineered the variable domains (Fv) of both antibodies to enable low-cost manufacturing at scale for distribution to pediatric populations, in alignment with WHO's preferred product guidelines. The engineered clone with the optimal manufacturing and drug property profile, MAM01, was advanced into clinical development.

Targeted CQA analytical control strategy for commercial antibody products: Replacing ion-exchange chromatography methods for charge heterogeneity with multi-attribute monitoring

Peptide mapping with mass spectrometry (MS) is an important tool for protein characterization in the biopharmaceutical industry. Historically, peptide mapping monitors post-translational modifications (PTMs) of protein products and process intermediates during development. Multi-attribute monitoring (MAM) methods have been used previously in commercial release and stability testing panels to ensure control of selected critical quality attributes (CQAs). Our goal is to use MAM methods as part of an overall analytical testing strategy specifically focused on CQAs, while removing or replacing historical separation methods that do not effectively distinguish CQAs from non-CQAs due to co-elution. For example, in this study, we developed a strategy to replace a profile-based ion-exchange chromatography (IEC) method using a MAM method in combination with traditional purity methods to ensure control of charge variant CQAs for a commercial antibody (mAb) drug product (DP). To support this change in commercial testing strategy, the charge variant CQAs were identified and characterized during development by high-resolution LC-MS and LC-MS/MS. The charge variant CQAs included PTMs, high molecular weight species, and low molecular weight species. Thus, removal of the IEC method from the DP specification was achieved using a validated LC-MS MAM method on a QDa system to directly measure the charge variant PTM CQAs in combination with size exclusion chromatography (SE-HPLC) and capillary electrophoresis (CE-SDS) to measure the non-PTM charge variant CQAs. Bridging data between the MAM, IEC, and SE-HPLC methods were included in the commercial marketing application to justify removing IEC from the DP specification. We have also used this MAM method as a test for identity to reduce the number of QC assays. This strategy has received approvals from several health authorities.

The Use of Mass Spectrometry in Therapeutic Protein Biologics License Applications: A Retrospective Review Revisited

Biologic license applications (BLAs) for 93 therapeutic proteins approved between 2016 and 2020 were analyzed for use of mass spectrometry (MS) as a follow up to a previous study that assessed MS use in BLAs from 2000 to 2015. Thirty percent of these BLAs were biosimilars, while only one biosimilar BLA was approved prior to 2016. This analysis evaluated the use of a variety of MS techniques and instrumentation. Results were further interpreted based on the relationship of MS use over time, between drug types, and between new drugs and biosimilars. MS data were included in 93 BLAs examined. The top eight quality attributes most assessed by MS in rank order were amino acid sequence, molecular mass, oxidation, disulfide bonds, deamidation, glycosylation, N-terminal sequence variants, and C-terminal sequence variants. These attributes were the same top attributes seen previously from BLAs approved between 2000 and 2015, and the use of MS to analyze them generally continued to increase across the new time frame. The average number of attributes analyzed by MS per BLA also continued to increase over the extended time frame of 21 years. High-resolution, accurate mass instrumentation such as the Orbitrap and time-of-flight (TOF) usage increased over time for all assessed attributes, while matrix-assisted laser desorption/ionization (MALDI)-TOF/(TOF) usage decreased. From highest to lowest rank, the top 11 attributes were antibody drug conjugate (ADC) characterization (i.e., drug load distribution/drug to antibody ratio (DAR), ADC and linkage site, and synthetic linker), isomerization, folding/higher-order structure (HOS), truncation, host cell proteins (HCPs), sequence variants (amino acid substitutions), succinimidation, glycation, PEGylation, charge variants, and oxidation.

Diagnostic utility of N-terminal TMPP labels for unambiguous identification of clipped sites in therapeutic proteins

Protein therapeutics are susceptible to clipping via enzymatic and nonenzymatic mechanisms that create neo-N-termini. Typically, neo-N-termini are identified by chemical derivatization of the N-terminal amine with (N-Succinimidyloxycarbonylmethyl)tris(2,4,6-trimethoxyphenyl)phosphonium bromide (TMPP) followed by proteolysis and mass spectrometric analysis. Detection of the TMPP-labeled peptide is achieved by mapping the peptide sequence to the product ion spectrum derived from collisional activation. The site-specific localization of the TMPP tag enables unambiguous determination of the true N-terminus or neo-N-termini. In addition to backbone product ions, TMPP reporter ions at m/z 573, formed via collision-induced dissociation, can be diagnostic for the presence of a processed N-termini. However, reporter ions generated by collision-induced dissociation may be uninformative because of their low abundance. We demonstrate a novel high-throughput LC-MS method for the facile generation of the TMPP reporter ion at m/z 533 and, in some instances m/z 590, upon electron transfer dissociation. We further demonstrate the diagnostic utility of TMPP labeled peptides derived from a total cell lysate shows high degree of specificity towards selective N-terminal labeling over labeling of lysine and tyrosine and highly-diagnostic Receiver Operating Characteristic's (ROC) of TMPP reporter ions of m/z 533 and m/z 590. The abundant generation of these reporters enables subsequent MS/MS by intensity and m/z-dependent triggering of complementary ion activation modes such as collision-induced dissociation, high-energy collision dissociation, or ultraviolet photo dissociation for subsequent peptide sequencing.

Addressing Acid-Catalyzed Deamidation and the Solubility of Hydrophobic Peptides in Multi-Attribute Method Workflows

Recently, we introduced an optimized and automated Multi-Attribute Method (MAM) workflow, which (a) significantly reduces the number of missed cleavages using an automated two-step digestion procedure and (b) dramatically reduces chromatographic peak tailing and carryover of hydrophobic peptides by implementing less retentive reversed-phase column chemistries. Here, further insights are provided on the impact of postdigest acidification and the importance of maintaining hydrophobic peptides in solution using strong chaotropic agents after digestion. We demonstrate how oxidation can significantly increase the solubility of hydrophobic peptides, a fact that can have a profound impact on quantitation of oxidation levels if care is not taken in MAM workflows. We conclude that (a) postdigestion acidification can result in significant acid-catalyzed deamidation during storage in an autosampler at 5 °C and (b) a strong chaotropic agent, such as guanidine hydrochloride, is critical for preventing loss of hydrophobic peptides through adsorption, which can result in (sometimes extreme) biases in quantitation of tryptophan oxidation levels. An optimized method is presented, which effectively addressed acid-catalyzed deamidation and solubility of hydrophobic peptides in MAM workflows.

Fully Unattended Online Protein Digestion and LC-MS Peptide Mapping

LC-MS based peptide mapping, i.e., proteolytic digestion followed by LC-MS/MS analysis, is the method of choice for protein primary structural characterization. Manual proteolytic digestion is usually a labor-intensive procedure. In this work, a novel method was developed for fully automated online protein digestion and LC-MS peptide mapping. The method generates LC-MS data from undigested protein samples without user intervention by utilizing the same HPLC system that performs the chromatographic separation with some additional modules. Each sample is rapidly digested immediately prior to its LC-MS analysis, minimizing artifacts that can grow over longer digestion times or digest storage times as in manual or automated offline digestion methods. In this report, we implemented the method on an Agilent 1290 Infinity II LC system equipped with a Multisampler. The system performs a complete digestion workflow including denaturation, disulfide reduction, cysteine alkylation, buffer exchange, and tryptic digestion. We demonstrated that the system is capable of digesting monoclonal antibodies and other proteins with excellent efficiency and is robust and reproducible and produces fewer artifacts than manually prepared digests. In addition, it consumes only a few micrograms of material as most of the digested sample protein is subjected to LC-MS analysis.

Compliance and regulatory considerations for the implementation of the multi-attribute-method by mass spectrometry in a quality control laboratory

Multi-attribute methods employing mass spectrometry are applied throughout the biopharmaceutical industry for product and process characterization purposes but are not yet widely accepted as a method for batch release and stability testing under the good manufacturing practice (GMP) regime, due to limited experience and level of comfort with the technical, compliance and regulatory aspects of its implementation at quality control (QC) laboratories. This article is the second part of a two-tiered publication aiming at providing guidance for implementation of the multi-attribute method by peptide mapping liquid chromatography mass spectrometry (MAM) in a QC laboratory. The first part [1] focuses on technical considerations, while this second part provides considerations related to GMP compliance and regulatory aspects. This publication has been prepared by a group of industry experts representing 14 globally acting major biotechnology companies under the umbrella of the European Federation of Pharmaceutical Industries and Associations (EFPIA) Manufacturing & Quality Expert Group (MQEG).

Method validation and new peak detection for the liquid chromatography-mass spectrometry multi-attribute method

The multi-attribute method (MAM) is a liquid chromatography-mass spectrometry (LC-MS) peptide mapping technique that has been proposed as a replacement for several conventional quality control (QC) methods for therapeutic proteins. In addition to quantification of multiple product quality attributes (PQAs), MAM can also monitor impurities using a new peak detection (NPD) feature. Here, results are provided from method validation and NPD studies of an MAM approach applied to rituximab as a model monoclonal antibody (mAb). Twenty-one rituximab PQAs were monitored, including oxidation, pyroglutamination, deamidation, lysine clipping, and glycosylation. The PQA monitoring aspect of the method was validated according to ICH Guidance. Accuracy, precision, specificity, detection and quantitation limits, linearity, range, and robustness were demonstrated for this MAM approach with minimal issues. All PQAs were successfully validated except for several oxidation sites, which did not pass intermediate precision criteria. The variability found in oxidation measurements was attributed to artificial oxidation during sample preparation and could likely be alleviated through several approaches. The NPD aspect of the method was also evaluated. A spike-in approach was used to assess the limits of detection and quantitation (LOD/LOQ) of the NPD feature of MAM. For NPD, the peak intensity threshold was found to be the most critical parameter for accurate detection of impurities since a low threshold can result in false positives while a high threshold can obscure the detection of true peaks. Overall, the MAM approach presented and validated here has been demonstrated to be suitable for both targeted monitoring of rituximab PQAs and non-targeted detection of new peaks that represent impurities.

Recent applications of quantitative mass spectrometry in biopharmaceutical process development and manufacturing

Biopharmaceutical products have seen rapid growth over the past few decades and continue to dominate the global pharmaceutical market. Aligning with the quality by design (QbD) framework and realization, recent advances in liquid chromatography-mass spectrometry (LC-MS) instrumentation and related techniques have enhanced biopharmaceutical characterization capabilities and have supported an increased development of biopharmaceutical products. Beyond its routine qualitative characterization, the quantitative feature of LC-MS has unique applications in biopharmaceutical process development and manufacturing. This review describes the recent applications and implications of the advancement of quantitative MS methods in biopharmaceutical process development, and characterization of biopharmaceutical product, product-related variants, and process-related impurities. We also provide insights on the emerging applications of quantitative MS in the lifecycle of biopharmaceutical product development including quality control in the Good Manufacturing Practice (GMP) environment and process analytical technology (PAT) practices during process development and manufacturing. Through collaboration with instrument and software vendors and regulatory agencies, we envision broader adoption of phase-appropriate quantitative MS-based methods for the analysis of biopharmaceutical products, which in turn has the potential to enable manufacture of higher quality products for patients.

A comprehensive strategy for the identification of biologics by liquid-chromatography-mass spectrometry for release testing in a regulated environment

Identification (ID) testing is a regulatory requirement for biopharmaceutical manufacturing, requiring robust, GMP-qualified assays that can distinguish the therapeutic from any other in the facility. Liquid Chromatography-Mass Spectrometry (LC-MS) is a powerful analytical tool used to identify and characterize biologics. While routinely leveraged for characterization, LC-MS is relatively rare in Quality Control (QC) settings due to its perceived complexity and scarcity of MS-trained personnel. However, employing LC-MS for identification of drug products has many advantages versus conventional ID techniques, including but not limited to its high specificity, rapid turn-around time, and ease of method execution. In this work, we outline the development and implementation of a comprehensive LC-MS based ID strategy for biologics release testing. Two main workflows (WFs) were developed: i) WF1, a subunit-based assay measuring the molecular weight of the light chain (LC) and heavy chain (HC) of an antibody upon reduction, and ii) WF2, intact mass measurement of the biologic upon N-deglycosylation by PNGase F. The proposed strategy is shown to be applicable for over 40 diverse model biologics including monoclonal antibodies (mAbs), biobetters such as antibody prodrugs/afucosylated mAbs, fusion proteins, multi-specific antibodies, Fabs, and large peptides, all with excellent mass accuracy (error typically < 20 ppm) and precision. It requires a single-step sample preparation and a single click to run and process the data upon method setup. This strategy has been successfully implemented for release testing in GMP labs. Challenges and considerations for the establishment of QC-friendly methods are discussed. It is also shown that these methods can be applied to the ID of more analytically complex biotherapeutics, such as fixed-dose combination (FDC) and drug products co-formulated with trace-level additives.

Use of single analytic tool to quantify both absolute N-glycosylation and glycan distribution in monoclonal antibodies

Recombinant proteins represent almost half of the top selling therapeutics-with over a hundred billion dollars in global sales-and their efficacy and safety strongly depend on glycosylation. In this study, we showcase a simple method to simultaneously analyze N-glycan micro- and macroheterogeneity of an immunoglobulin G (IgG) by quantifying glycan occupancy and distribution. Our approach is linear over a wide range of glycan and glycoprotein concentrations down to 25 ng/mL. Additionally, we present a case study demonstrating the effect of small molecule metabolic regulators on glycan heterogeneity using this approach. In particular, sodium oxamate (SOD) decreased Chinese hamster ovary (CHO) glucose metabolism and reduced IgG glycosylation by 40% through upregulating reactive oxygen species (ROS) and reducing the UDP-GlcNAc pool, while maintaining a similar glycan profile to control cultures. Here, we suggest glycan macroheterogeneity as an attribute should be included in bioprocess screening to identify process parameters that optimize culture performance without compromising antibody quality.

Evolution of Vaccines Formulation to Tackle the Challenge of Anti-Microbial Resistant Pathogens

The increasing diffusion of antimicrobial resistance (AMR) across more and more bacterial species emphasizes the urgency of identifying innovative treatment strategies to counter its diffusion. Pathogen infection prevention is among the most effective strategies to prevent the spread of both disease and AMR. Since their discovery, vaccines have been the strongest prophylactic weapon against infectious diseases, with a multitude of different antigen types and formulative strategies developed over more than a century to protect populations from different pathogens. In this review, we review the main characteristics of vaccine formulations in use and under development against AMR pathogens, focusing on the importance of administering multiple antigens where possible, and the challenges associated with their development and production. The most relevant antigen classes and adjuvant systems are described, highlighting their mechanisms of action and presenting examples of their use in clinical trials against AMR. We also present an overview of the analytical and formulative strategies for multivalent vaccines, in which we discuss the complexities associated with mixing multiple components in a single formulation. This review emphasizes the importance of combining existing knowledge with advanced technologies within a Quality by Design development framework to efficiently develop vaccines against AMR pathogens.

Multiattribute Monitoring of Aggregates and Charge Variants of Monoclonal Antibody through Native 2D-SEC-MS-WCX-MS

Monitoring of critical quality attributes such as size and charge-related heterogeneities is essential for biopharmaceutical manufacturers. Size-exclusion chromatography (SEC) is the preferred analytical technique for the quantification of aggregates and fragments in the product, whereas weak-cation exchange chromatography (WCX) is widely used for the characterization of charge variants of biotherapeutic products, in particular monoclonal antibodies (mAbs). Multiattribute monitoring offers the ability to monitor these attributes in a single run flow using two-dimensional liquid chromatography (2D-LC). Typically, in this approach, only the second-dimension samples are directly analyzed through mass spectrometry, as the first dimension has limitations concerning direct coupling with mass spectrometry. In the present study, a novel 2D-SEC-MS/WCX-MS workflow has been proposed, in which chromatography of both dimensions (D¹ and D²) was directly coupled with mass spectrometry, through which size-related and charge-related variants of monoclonal antibody mAb A were analyzed simultaneously in their native form. In comparison to stand-alone SEC and WCX methods, this method enables simultaneous analysis of size and charge variants in a single workflow without manual intervention, allowing analysis of low abundant variants. Further, this method has 75% less sample requirement and a shorter analysis time (25 min vs 90 min) when size and charge variants were analyzed individually. The proposed native 2D-LC-MS workflow was used to analyze a stressed sample of mAb A, in which D¹ analysis revealed the presence of aggregates (8-20%), which were primarily dimers, whereas D² analysis showed an increment in acidic variants (9-21%).

Method for detecting rare differences between two LC-MS runs

LC-MS based multi-attribute methods (MAM) have drawn substantial attention due to their capability of simultaneously monitoring a large number of quality attributes of a biopharmaceutical product. For successful implementation of MAM, it is usually considered a requirement that the method is capable of detecting any new or missing peaks in the sample when compared to a control. Comparing a sample to a control for rare differences is also commonly practiced in many fields for investigational purpose. Because MS signal variability differs greatly between signals of different intensities, this type of comparison is often challenging, especially when the comparison is made without enough replicates. In this report we describe a statistical method for detecting rare differences between two very similar samples without replicate analyses. The method assumes that an overwhelming majority of components have equivalent abundance between the two samples, and signals with similar intensities have similar relative variability. By analyzing several monoclonal antibody peptide mapping datasets, we demonstrated that the method is suitable for new-peak detection for MAM as well as for other applications when rare differences between two samples need to be detected. The method greatly reduced false positive rate without a significant increase of false negative rate.

Technical considerations for the implementation of the Multi-Attribute-Method by mass spectrometry in a Quality Control laboratory

Multi-attribute methods employing mass spectrometry are applied throughout the biopharmaceutical industry for product and process characterization purposes but are not yet widely accepted as a method for batch release and stability testing under good manufacturing practice (GMP) due to limited experience and level of comfort with the technical, compliance and regulatory aspects of its implementation at quality control (QC) laboratories. Here, current literature related to the development and application of the multi-attribute method by peptide mapping liquid chromatography mass spectrometry (MAM) is compiled with the aim of providing guidance for the implementation of MAM in a QC laboratory. This article, focusing on technical considerations, is the first part of a two-tiered publication, whereby the second part will focus on GMP compliance and regulatory aspects. This publication has been prepared by a group of industry experts representing 14 globally acting major biotechnology companies under the umbrella of the European Federation of Pharmaceutical Industries and Associations (EFPIA) Manufacturing & Quality Expert Group (MQEG).

Innovative Metrics for Reporting and Comparing the Glycan Structural Profile in Biotherapeutics

Glycosylation is a critical quality attribute in biotherapeutics, impacting properties such as protein stability, solubility, clearance rate, efficacy, immunogenicity, and safety. Due to the heterogenic and complex nature of protein glycosylation, comprehensive characterization is demanding. Moreover, the lack of standardized metrics for evaluating and comparing glycosylation profiles hinders comparability studies and the establishment of manufacturing control strategies. To address both challenges, we propose a standardized approach based on novel metrics for a comprehensive glycosylation fingerprint which greatly facilitates the reporting and objective comparison of glycosylation profiles. The analytical workflow is based on a liquid chromatography-mass spectrometry-based multi-attribute method. Based on the analytical data, a matrix of glycosylation-related quality attributes, both at site-specific and whole molecule level, are computed, which provide metrics for a comprehensive product glycosylation fingerprint. Two case studies illustrate the applicability of the proposed indices as a standardized and versatile approach for reporting all dimensions of the glycosylation profile. The proposed approach further facilitates the assessments of risks associated with changes in the glycosylation profile that may affect efficacy, clearance, and immunogenicity.

Intact Mass Analysis–Based Multi-Attribute Methods (iMAMs) for Characterization of Biopharmaceuticals

Multi-attribute methods (MAMs) are becoming increasingly popular for their ability to analyze multiple critical quality attributes (CQA) in a single workflow. This capability becomes particularly attractive for a product class such as monoclonal antibodies, which are large and complex, and have many CQAs that need to be monitored and controlled during their manufacturing so as to deliver consistent product quality. In an earlier installment, we discussed the role of liquid chromatography and mass spectrometry in MAMs. In this article, we focus on intact mass analysis–based multi-attribute methods (iMAMs), a suitable alternative that can complement standard MAMs or be used when there is a need for rapid turnaround and monitoring of only a limited number of CQAs. Multiple case studies are presented to elucidate this concept.

A Robust Purity Method for Biotherapeutics Using New Peak Detection in an LC-MS-Based Multi-Attribute Method

New peak detection (NPD), as part of the LC-MS-based multi-attribute method (MAM), allows for sensitive and unbiased detection of new or changing site-specific attributes between a sample and reference that is not possible with conventional UV or fluorescence detection-based methods. MAM with NPD can serve as a purity test that can establish whether a sample and the reference are similar. The broad implementation of NPD in the biopharmaceutical industry has been limited by the potential presence of false positives or artifacts, which increase the analysis time and can trigger unnecessary investigations of product quality. Our novel contributions to the success of NPD are the curation of false positives, use of the known peak list concept, pairwise analysis approach, and the development of a NPD system suitability control strategy. In this report, we also introduce a unique experimental design utilizing sequence variant co-mixes to measure NPD performance. We show that NPD has superior performance relative to conventional control system methods in the detection of an unexpected change as compared with the reference. NPD is a new frontier in purity testing that reduces subjectivity, need for analyst intervention, and potential for missing unexpected product quality changes.

Analytical Performance Evaluation of Identity, Quality-Attribute Monitoring and new Peak Detection in a Platform Multi-Attribute Method Using Lys-C Digestion for Characterization and Quality Control of Therapeutic Monoclonal Antibodies

The use of multi-attribute method (MAM) for identity and purity testing of biopharmaceuticals offers the ability to complement and replace multiple conventional analytical technologies with a single mass spectrometry (MS) method. Phase-appropriate method validation is one major consideration for the implementation of MAM in a current Good Manufacturing Practice (cGMP) environment. We developed a MAM workflow for therapeutic monoclonal antibodies (mAbs) with optimized sample preparation using lysyl endopeptidase (Lys-C) digestion. In this study, we evaluated the assay performances of this platform MAM workflow for identity, product quality attributes (PQAs) monitoring and new peak detection (NPD) for single and coformulated mAbs. An IgG4 mAb-1 and its coformulations were used as model molecules in this study. The assay performance evaluation demonstrated the full potential of the platform MAM approach for its intended use for characterization and quality control of single mAb-1 and mAb-1 in its coformulations. To the best of our knowledge, this is the first performance evaluation of MAM for mAb identity, PQA monitoring, and new peak detection (NPD) in a single assay, featuring 1) the first performance evaluation of MAM for PQA monitoring using Lys-C digestion with a high-resolution MS, 2) a new approach for mAb identity testing capable of distinguishing single mAb from coformulations using MAM, and 3) the performance evaluation of NPD for MAM with Lys-C digestion. The developed platform MAM workflow and the MAM performance evaluation paved the way for its GMP qualification and enabled clinical release of mAb-1 in GMP environment with MAM.

Analytical Techniques for the Characterization and Quantification of Monoclonal Antibodies

Monoclonal antibodies (mAbs) are a fast-growing class of biopharmaceuticals. They are widely used in the identification and detection of cell makers, serum analytes, and pathogenic agents, and are remarkably used for the cure of autoimmune diseases, infectious diseases, or malignancies. The successful application of therapeutic mAbs is based on their ability to precisely interact with their appropriate target sites. The precision of mAbs rely on the isolation techniques delivering pure, consistent, stable, and safe lots that can be used for analytical, diagnostic, or therapeutic applications. During the creation of a biologic, the key quality features of a particular mAb, such as structure, post-translational modifications, and activities at the biomolecular and cellular levels, must be characterized and profiled in great detail. This implies the requirement of powerful state of the art analytical techniques for quality control and characterization of mAbs. Until now, various analytical techniques have been developed to characterize and quantify the mAbs according to the regulatory guidelines. The present review summarizes the major techniques used for the analyses of mAbs which include chromatographic, electrophoretic, spectroscopic, and electrochemical methods in addition to the modifications in these methods for improving the quality of mAbs. This compilation of major analytical techniques will help students and researchers to have an overview of the methodologies employed by the biopharmaceutical industry for structural characterization of mAbs for eventual release of therapeutics in the drug market.

Development and optimization of a LC-MS based multi-attribute method (MAM) workflow for characterization of therapeutic Fc-fusion protein

The growing complexity of novel biopharmaceutical formats, such as Fc-fusion proteins, in increasingly competitive environment has highlighted the need of high-throughput analytical platforms. Multi-attribute method (MAM) is an emerging analytical technology that utilizes liquid chromatography coupled with mass spectrometry to monitor critical quality attributes (CQAs) in biopharmaceuticals. MAM is intended to supplement or replace the conventional chromatographic and electrophoretic approaches used for quality control and drug release purpose. In this investigation, we have developed an agile sample preparation approach for deploying MAM workflow for a complex VEGFR-targeted therapeutic Fc-fusion protein. Initially, a systematic time course evaluation of tryptic digestion step was performed to achieve maximum amino acid sequence coverage of >96.5%, in a short duration of 2 h, with minimum assay artifacts. This approach facilitated precise identification of five sites of N-glycosylation with successful monitoring of other CQAs such as deamidation, oxidation, etc. Subsequently, the developed MAM workflow with suitable tryptic digestion time was qualified according to the International council for harmonisation (i.e. ICH) Q2R1 guidelines for method validation. Post-validation, the analytical workflow was also evaluated for its capability to identify unknown moieties, termed as 'New Peak Detection' (i.e. NPD), and assess fold change between the reference and non-reference samples, in a representative investigation of pH stress study. The study, thus, demonstrated the suitability of the MAM workflow for characterization of heavily glycosylated Fc-fusion proteins. Moreover, its NPD feature could offer an all-encompassing view if applied for forced degradation and stability studies.

Comprehensive multi-attribute method workflow for biotherapeutic characterization and current good manufacturing practices testing

The multi-attribute method (MAM) is a liquid chromatography-mass spectrometry (LC-MS)-based method that is used to directly characterize and monitor numerous product quality attributes (PQAs) at the amino acid level of a biopharmaceutical product. MAM enables identity testing based on primary sequence verification, detection and quantitation of post-translational modifications and impurities. This ability to simultaneously and directly determine PQAs of therapeutic proteins makes MAM a more informative, streamlined and productive workflow than conventional chromatographic and electrophoretic assays. MAM relies on proteolytic digestion of the sample followed by reversed-phase chromatographic separation and high-resolution LC-MS analysis in two phases. First, a discovery study to determine quality attributes for monitoring is followed by the creation of a targeted library based on high-resolution retention time plus accurate mass analysis. The second aspect of MAM is the monitoring phase based on the target peptide library and new peak detection using differential analysis of the data to determine the presence, absence or change of any species that might affect the activity or stability of the biotherapeutic. The sample preparation process takes between 90 and 120 min, whereas the time spent on instrumental and data analyses might vary from one to several days for different sample sizes, depending on the complexity of the molecule, the number of attributes to be monitored and the information to be detailed in the final report. MAM is developed to be used throughout the product life cycle, from process development through upstream and downstream processes to quality control release or under current good manufacturing practices regulations enforced by regulatory agencies.

Optimized Multi-Attribute Method Workflow Addressing Missed Cleavages and Chromatographic Tailing/Carry-Over of Hydrophobic Peptides

Peptide mapping by liquid chromatography mass spectrometry (LC-MS) and the related multi-attribute method (MAM) are well-established analytical tools for verification of the primary structure and mapping/quantitation of co- and post-translational modifications (PTMs) or product quality attributes in biopharmaceutical development. Proteolytic digestion is a key step in peptide mapping workflows, which traditionally is labor-intensive, involving multiple manual steps. Recently, simple high-temperature workflows with automatic digestion were introduced, which facilitate robustness and reproducibility across laboratories. Here, a modified workflow with an automatic digestion step is presented, which includes a two-step digestion at high and low temperatures, as opposed to the original one-step digestion at a high temperature. The new automatic digestion workflow significantly reduces the number of missed cleavages, obtaining a more complete digestion profile. In addition, we describe how chromatographic peak tailing and carry-over is dramatically reduced for hydrophobic peptides by switching from the traditional C18 reversed-phase (RP) column chemistry used for peptide mapping to a less retentive C4 column chemistry. No negative impact is observed on MS/MS-derived sequence coverage when switching to a C4 column chemistry. Overall, the new peptide mapping workflow significantly reduces the number of missed cleavages, yielding more robust and simple data interpretation, while providing dramatically reduced tailing and carry-over of hydrophobic peptides.

Overcoming Incomplete Peptide Mapping of Antibody Complementarity-Determining Regions with Alternate Digestion Workflows

Peptide mapping of antibodies is an essential method to monitor peptide modifications in antibody lots that could affect the safety and efficacy of the product. Conventional protocols rely on protein digestion using proteases, such as trypsin, before mapping with mass spectrometry (MS). However, trypsin digestion may cause incomplete mapping of peptides, especially those that include highly hydrophobic peptides. Here, we show how pepsin can be used as an alternative and complementary protease for digestion that allows for improved sequence coverage, especially in proteins with highly hydrophobic regions. We also show that using guanidine hydrochloride (GuHCl) post-digestion improves peptide mapping results. Overall, these two methods—pepsin digestion and GuHCl post-digestion—can be used to provide more comprehensive antibody peptide maps, thereby enabling more thorough quality checking of biopharmaceutical products.

Attribute Analytics Performance Metrics from the MAM Consortium Interlaboratory Study

The multi-attribute method (MAM) was conceived as a single assay to potentially replace multiple single-attribute assays that have long been used in process development and quality control (QC) for protein therapeutics. MAM is rooted in traditional peptide mapping methods; it leverages mass spectrometry (MS) detection for confident identification and quantitation of many types of protein attributes that may be targeted for monitoring. While MAM has been widely explored across the industry, it has yet to gain a strong foothold within QC laboratories as a replacement method for established orthogonal platforms. Members of the MAM consortium recently undertook an interlaboratory study to evaluate the industry-wide status of MAM. Here we present the results of this study as they pertain to the targeted attribute analytics component of MAM, including investigation into the sources of variability between laboratories and comparison of MAM data to orthogonal methods. These results are made available with an eye toward aiding the community in further optimizing the method to enable its more frequent use in the QC environment.

Mass spectrometry-based multi-attribute method for mutation analysis in the early development of therapeutic proteins

The early intervention is essential, and later development cannot compensate for this initial generation of an antibody drug. Especially for sequence variants (SVs), should cause concern during the early bioprocess development. The advancement of bioprocess development is paralleled by development of state-of-the-art analytical methods that will provide further information. In the present study, a mass spectrometry (MS)-based multi-attribute method (MAM) was used to simultaneously monitor the SVs and other quality attributes in the early bioprocess development of ofatumumab, and a sequence variant (SV) was detected by a subunit-based MAM. Subsequently, the variant was further identified by MS/MS and confirmed by adding a synthetic peptide. Furthermore, the content of the SV was detected via DNA sequencing. The levels of the variant (T175A mutant) in the light chain were demonstrate to be nearly consistent at the DNA and protein levels, suggesting that the mutation may have negligible effect on both the transcriptional and translational levels. Collectively, these results indicate that broad-spectrum, rapid, and accurate platform such as MS-based MAM should be implemented to quality control for the early development of therapeutic proteins, it will also be important to establish an effective and integrated MAM to control SVs during therapeutic proteins development.

Characterization of outcomes of amino acid modifications using a combinatorial approach to reveal physical and structural perturbations: A case study using trastuzumab biosimilar

Biopharmaceuticals, such as monoclonal antibodies, are considered as life-saving drugs for autoimmune diseases, cancer and infectious diseases. However, biotherapeutics tend to undergo chemical degradation during various stages of manufacturing. The conditions of chemical degradation, along with the physical degradation pathways, have a direct influence on the overall stability, safety and efficacy of these therapeutics. While site-specific chemical changes have been well-explored and investigated using various analytical approaches, the resulting conformational and structural changes have not been much studied. Thus, we explored various biophysical techniques for assessing the influence of three representatives forced degradation conditions viz. oxidation, deamidation, and glycation, in a model therapeutic trastuzumab biosimilar. The site-specific modifications caused by these stress conditions were analysed using high resolution mass spectrometry. While their thermodynamic and conformational consequences were investigated by using differential scanning colorimetry (Nano-DSC), circular dichroism (CD) spectroscopy, analytical ultracentrifugation (AUC), and dynamic light scattering (DLS). The investigated stress conditions resulted in reduced thermodynamic stability of mAb, as confirmed using Nano-DSC. Secondary structure analysis performed with CD spectroscopy indicated detectable structural alterations in the beta sheets of stressed samples. DLS and SV-AUC studies demonstrated an enhanced level of aggregation and fragmentation in presence of all stress conditions. Thus, the biophysical analytical toolkits, when used simultaneously, could offer deeper insights into the subtle conformational changes that result from site-specific chemical modifications in mAbs. Hence, these analytical approaches may serve as significant additions to the battery of techniques used for forced degradation analysis of biopharmaceuticals.

Recent Advances and Future Directions in Downstream Processing of Therapeutic Antibodies

Despite the advent of many new therapies, therapeutic monoclonal antibodies remain a prominent biologics product, with a market value of billions of dollars annually. A variety of downstream processing technological advances have led to a paradigm shift in how therapeutic antibodies are developed and manufactured. A key driver of change has been the increased adoption of single-use technologies for process development and manufacturing. An early-stage developability assessment of potential lead antibodies, using both in silico and high-throughput experimental approaches, is critical to de-risk development and identify molecules amenable to manufacturing. Both statistical and mechanistic modelling approaches are being increasingly applied to downstream process development, allowing for deeper process understanding of chromatographic unit operations. Given the greater adoption of perfusion processes for antibody production, continuous and semi-continuous downstream processes are being increasingly explored as alternatives to batch processes. As part of the Quality by Design (QbD) paradigm, ever more sophisticated process analytical technologies play a key role in understanding antibody product quality in real-time. We should expect that computational prediction and modelling approaches will continue to be advanced and exploited, given the increasing sophistication and robustness of predictive methods compared to the costs, time, and resources required for experimental studies.

Implementing 1.5 mm internal diameter columns into analytical workflows

The use of smaller column diameters in liquid chromatography (LC) is often associated with capillary LC. Although there are many analytical benefits gained by adapting this format, routine use continues to be challenging due to column fragility and extra column dispersion. Bridging the gap between routinely used 2.1 mm columns and capillary bore columns allows for a sequential but far from insignificant increase in performance without the need for specialized equipment associated with very low dispersion LC systems. Moreover, an incremental decrease in column internal diameter (i.d.) allows for similar mass load (avoiding column overload that may be observed in much larger decreases in i.d. without trapping) and thus an increase in measured signal. As such, 1.5 mm i.d. columns provide an alternative intermediate dimension between the more regularly used 2.1 mm i.d. columns and 1 mm i.d. columns. These columns balance an increase in sensitivity compared to 2.1 mm i.d. columns (theoretically doubling the time-domain peak area in mass sensitive detectors for the same mass load), while mitigating the efficiency losses due to extra-column dispersion effects that are commonly observed with 1.0 mm i.d. columns. Here, the use of 1.5 mm i.d. columns was applied to LC/UV analysis of small molecules and LC/MS methods for the analysis of monoclonal antibodies. With equivalent mass load on column, the 1.5 mm i.d. columns provide two-to-threefold improvement in analyte peak area signal for small molecules as well as intact, subunit, and peptide levels of antibody analysis. Peak height was also increased using the 1.5 mm i.d. column, although the scale of increase varies between isocratic and gradient modes, likely due to differences in system dispersion effects and variation in electrospray ionization efficiency at different flow rates.

High-Resolution Demultiplexing (HRdm) Ion Mobility Spectrometry-Mass Spectrometry for Aspartic and Isoaspartic Acid Determination and Screening

Isomeric peptide analyses are an analytical challenge of great importance to therapeutic monoclonal antibody and other biotherapeutic product development workflows. Aspartic acid (Asp, D) to isoaspartic acid (isoAsp, isoD) isomerization is a critical quality attribute (CQA) that requires careful control, monitoring, and quantitation during the drug discovery and production processes. While the formation of isoAsp has been implicated in a variety of disease states such as autoimmune diseases and several types of cancer, it is also understood that the formation of isoAsp results in a structural change impacting efficacy, potency, and immunogenic properties, all of which are undesirable. Currently, lengthy ultrahigh-performance liquid chromatography (UPLC) separations are coupled with MS for CQA analyses; however, these measurements often take over an hour and drastically limit analysis throughput. In this manuscript, drift tube ion mobility spectrometry-mass spectrometry (DTIMS-MS) and both a standard and high-resolution demultiplexing approach were utilized to study eight isomeric Asp and isoAsp peptide pairs. While the limited resolving power associated with the standard DTIMS analysis only separated three of the eight pairs, the application of HRdm distinguished seven of the eight and was only unable to separate DL and isoDL. The rapid high-throughput HRdm DTIMS-MS method was also interfaced with both flow injection and an automated solid phase extraction system to present the first application of HRdm for isoAsp and Asp assessment and demonstrate screening capabilities for isomeric peptides in complex samples, resulting in a workflow highly suitable for biopharmaceutical research needs.

Online HPLC–HRMS Platform: The Next-Generation Process Analytical Technology Tool for Real-Time Monitoring of Antibody Quality Attributes in Biopharmaceutical Processes

Online monitoring of critical quality attributes (CQAs) directly within the bioreactor can provide the basis for advanced processing of therapeutics production, including automated real-time monitoring, feedback control process intensification, smart manufacturing, and real-time release testing. This paper presents recent developments in online high performance liquid chromatography–high-resolution mass spectrometry (HPLC–HRMS) platforms as a promising process analytical technology (PAT) tool for real-time monitoring of antibody quality attributes (QAs) in biopharmaceutical processes. This technology can be used to monitor multiple CQAs and process parameters during cell culture production, enabling real-time decisions.

New Aspects in the Integration of MS Technologies in the Biopharmaceutical Industry

In the past decade, advances in both separations and mass spectrometry (MS) technologies have enabled new, streamlined, and data-rich approaches to monitor product quality attributes and their relationship with process parameters throughout the lifecycle of therapeutic proteins. As we enter a new decade of technology and method development, MS-based approaches utilized in the biopharmaceutical industry are evolving further. In this mini-review, we explore key developments that could inspire and improve the future of therapeutic protein development.

Development of a comprehensive approach for performance evaluation of a quantitative multi-attribute method as a quality control method

The multi-attribute method has been recognized as an elegant quantification tool for post-translational modifications (PTMs) of therapeutic proteins, since it can evaluate several attributes spontaneously and site-specifically. Here, the abundance of PTMs calculated by three different types of formula were compared and there was little difference among the results. For the method evaluation, two different kinds of peptides were used as internal standards (ISs) and one of the IS was used as the "standard peak" to define the signal strength of MS. They are also used for system suitability testing to verify whether the condition or sensitivity of mass spectrometry are high enough to evaluate the minor components by confirming the recovery rate of one IS to the another. This system is beneficial that since we have defined the limit of quantification as a certain ratio to IS, consistent MS intensity is applied as the threshold across all detected peaks.

Analytical Similarity Assessment of Biosimilars: Global Regulatory Landscape, Recent Studies and Major Advancements in Orthogonal Platforms

Biopharmaceuticals are one of the fastest-growing sectors in the biotechnology industry. Within the umbrella of biopharmaceuticals, the biosimilar segment is expanding with currently over 200 approved biosimilars, globally. The key step towards achieving a successful biosimilar approval is to establish analytical and clinical biosimilarity with the innovator. The objective of an analytical biosimilarity study is to demonstrate a highly similar profile with respect to variations in critical quality attributes (CQAs) of the biosimilar product, and these variations must lie within the range set by the innovator. This comprises a detailed comparative structural and functional characterization using appropriate, validated analytical methods to fingerprint the molecule and helps reduce the economic burden towards regulatory requirement of extensive preclinical/clinical similarity data, thus making biotechnological drugs more affordable. In the last decade, biosimilar manufacturing and associated regulations have become more established, leading to numerous approvals. Biosimilarity assessment exercises conducted towards approval are also published more frequently in the public domain. Consequently, some technical advancements in analytical sciences have also percolated to applications in analytical biosimilarity assessment. Keeping this in mind, this review aims at providing a holistic view of progresses in biosimilar analysis and approval. In this review, we have summarized the major developments in the global regulatory landscape with respect to biosimilar approvals and also catalogued biosimilarity assessment studies for recombinant DNA products available in the public domain. We have also covered recent advancements in analytical methods, orthogonal techniques, and platforms for biosimilar characterization, since 2015. The review specifically aims to serve as a comprehensive catalog for published biosimilarity assessment studies with details on analytical platform used and critical quality attributes (CQAs) covered for multiple biotherapeutic products. Through this compilation, the emergent evolution of techniques with respect to each CQA has also been charted and discussed. Lastly, the information resource of published biosimilarity assessment studies, created during literature search is anticipated to serve as a helpful reference for biopharmaceutical scientists and biosimilar developers.

Automated multi-attribute method sample preparation using high-throughput buffer exchange tips

RATIONALE

The multi-attribute method (MAM) has become a valuable mass spectrometry (MS)-based tool that can identify and quantify the site-specific product attributes and purity information for biotherapeutics such as monoclonal antibodies (mAbs) and fusion molecules in recent years. As we expand the use of the MAM at various stages of drug development, it is critical to enhance the sample preparation throughput without additional chemical modifications and variability.

METHODS

In this study, a fully automated MAM sample preparation protocol is presented, where rapid desalting in less than 15 minutes is achieved using miniaturized size-exclusion chromatography columns in pipette tips on an automated liquid handler. The peptide samples were analyzed using an electrospray ionization (ESI) orbitrap mass spectrometer coupled to an ultra-high-performance liquid chromatography (UHPLC) system with a dual column switching system.

RESULTS

No significant change was observed in product attributes and their quantities compared with manual, low-artifact sample preparation. The sample recovery using the buffer exchange tips was greatly enhanced over the manual spin cartridges while still demonstrating excellent reproducibility for a wide variety of starting sample concentrations. Unlike a plate desalting system, the individual columns provide flexibility in the number of samples prepared at a time and sample locations within plates.

CONCLUSIONS

This automated protocol enables the preparation of up to 96 samples with less "at-bench" time than the manual preparation of a smaller batch of samples, thereby greatly facilitating support of process development and the use of the MAM in quality control.

Multi attribute method implementation using a High Resolution Mass Spectrometry platform: From sample preparation to batch analysis

Quality control of biopharmaceuticals such as monoclonal antibodies (mAbs) has been evolving and becoming more challenging as the requirements of the regulatory agencies increase due to the demanding complexity of products under evaluation. Mass Spectrometry (MS)-based methods such as the multi-attribute method (MAM) are being explored to achieve a deeper understanding of the attributes critical for the safety, efficacy, and quality of these products. MAM uses high mass accuracy/high-resolution MS data that enables the direct and simultaneous monitoring of relevant product quality attributes (PQAs, in particular, chemical modifications) in a single workflow, replacing several orthogonal methods, reducing time and costs associated with these assays. Here we describe a MAM implementation process using a QTOF high resolution platform. Method implementation was accomplished using NIST (National Institute for Standards and Technology) mAb reference material and an in-process mAb sample. PQAs as glycosylation profiles, methionine oxidation, tryptophan dioxidation, asparagine deamidation, pyro-Glu at N-terminal and glycation were monitored. Focusing on applications that require batch analysis and high-throughput, sample preparation and LC-MS parameters troubleshooting are discussed. This MAM workflow was successfully explored as reference analytical tool for comprehensive characterization of a downstream processing (DSP) polishing platform and for a comparability study following technology transfer between different laboratories.

Modern Sensor Tools and Techniques for Monitoring, Controlling, and Improving Cell Culture Processes

The growing biopharmaceutical industry has reached a level of maturity that allows for the monitoring of numerous key variables for both process characterization and outcome predictions. Sensors were historically used in order to maintain an optimal environment within the reactor to optimize process performance. However, technological innovation has pushed towards on-line in situ continuous monitoring of quality attributes that could previously only be estimated off-line. These new sensing technologies when coupled with software models have shown promise for unique fingerprinting, smart process control, outcome improvement, and prediction. All this can be done without requiring invasive sampling or intervention on the system. In this paper, the state-of-the-art sensing technologies and their applications in the context of cell culture monitoring are reviewed with emphasis on the coming push towards industry 4.0 and smart manufacturing within the biopharmaceutical sector. Additionally, perspectives as to how this can be leveraged to improve both understanding and outcomes of cell culture processes are discussed.

A competitive binding-mass spectrometry strategy for high-throughput evaluation of potential critical quality attributes of therapeutic monoclonal antibodies

Therapeutic monoclonal antibodies (mAbs) have a propensity to host a large number of chemical and enzymatical modifications that need to be properly assessed for their potential impact on target binding. Traditional strategies of assessing the criticality of these attributes often involve a laborious and low-throughput variant enrichment step prior to binding affinity measurement. Here, we developed a novel competitive binding-based enrichment strategy followed by mass spectrometry analysis (namely, competitive binding-MS) to achieve high-throughput evaluation of potential critical quality attributes in therapeutic mAbs. Leveraging the differences in target binding capability under competitive binding conditions, the criticality of multiple mAb attributes can be simultaneously evaluated by quantitative mass spectrometry analysis. The utility of this new workflow was demonstrated in three mAb case studies, where different post-translational modifications occurring within the complementarity-determining regions were successfully interrogated for their impact on antigen binding. As this workflow does not require prior enrichment (e.g., by forced degradation or liquid chromatography fractionation) of the variants, it is particularly valuable during the mAb candidate developability assessment, where fast turn-around time is highly desired to assist candidate selection.

Abbreviations: ACN: acetonitrile; ADCC: antibody-dependent cell-mediated cytotoxicity; AEX: anion exchange chromatography; bsAb: bispecific antibody; CDC: complement-dependent cytotoxicity; CDR: complementarity-determining region; CML: carboxymethylation; CQA: critical quality attribute; DDA: data-dependent acquisition; DMSO: dimethyl sulfoxide; DTT: dithiothreitol; FA: formic acid; Fab: Fragment antigen-binding; FcRn: neonatal Fc receptor; HC: heavy chain; HIC: hydrophobic interaction chromatography; IAA: iodoacetamide; IEX: ion exchange chromatography; LC: light chain; mAb monoclonal antibody; msAb: monospecific antibody; MS: mass spectrometry; PBS: phosphate-buffered saline; pI: isoelectric point; PTM: post-translational modification; SCX: strong cation exchange chromatography; SEC: size exclusion chromatography; SPR: surface plasmon resonance; XIC: extracted ion chromatography.